Another trial of Avastin as a treatment for metastatic breast cancer has fallen short. The Genentech cancer drug lost its approval last month as a treatment for breast cancer after years of emotional and political controversy. The latest trial, had it been more successful, could have paved the way for a new approval. That is because it tested Avastin as a treatment for the roughly 20 percent of breast cancers that have elevated levels of the Her2 protein. The old and now revoked approval was for the other 80 percent of tumors that are Her2-negative. All the patients in the trial received Genentech’s Herceptin, a mainstay of treatment for Her2-positive cancer, as well as the chemotherapy drug docetaxel. Some women were randomized to also receive Avastin.